linux-kernel - Re: [PATCH v4 5/6] alloc_tag: introduce pgtag_ref

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAJuCfpFEYm-YT7AS6TzOMdLNtuS1E7KJuWJ8YeL9ro2L+3Wb9g@mail.gmail.com>
Date: Thu, 24 Oct 2024 09:25:22 -0700
From: Suren Baghdasaryan <surenb@...gle.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: kent.overstreet@...ux.dev, corbet@....net, arnd@...db.de, 
	mcgrof@...nel.org, rppt@...nel.org, paulmck@...nel.org, thuth@...hat.com, 
	tglx@...utronix.de, bp@...en8.de, xiongwei.song@...driver.com, 
	ardb@...nel.org, david@...hat.com, vbabka@...e.cz, mhocko@...e.com, 
	hannes@...xchg.org, roman.gushchin@...ux.dev, dave@...olabs.net, 
	willy@...radead.org, liam.howlett@...cle.com, pasha.tatashin@...een.com, 
	souravpanda@...gle.com, keescook@...omium.org, dennis@...nel.org, 
	jhubbard@...dia.com, urezki@...il.com, hch@...radead.org, petr.pavlu@...e.com, 
	samitolvanen@...gle.com, da.gomez@...sung.com, yuzhao@...gle.com, 
	vvvvvv@...gle.com, rostedt@...dmis.org, iamjoonsoo.kim@....com, 
	rientjes@...gle.com, minchan@...gle.com, kaleshsingh@...gle.com, 
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-arch@...r.kernel.org, linux-mm@...ck.org, 
	maple-tree@...ts.infradead.org, linux-modules@...r.kernel.org, 
	kernel-team@...roid.com
Subject: Re: [PATCH v4 5/6] alloc_tag: introduce pgtag_ref_handle to abstract
 page tag references

On Wed, Oct 23, 2024 at 2:09 PM Suren Baghdasaryan <surenb@...gle.com> wrote:
>
> On Wed, Oct 23, 2024 at 2:00 PM Andrew Morton <akpm@...ux-foundation.org> wrote:
> >
> > On Wed, 23 Oct 2024 10:07:58 -0700 Suren Baghdasaryan <surenb@...gle.com> wrote:
> >
> > > To simplify later changes to page tag references, introduce new
> > > pgtag_ref_handle type. This allows easy replacement of page_ext
> > > as a storage of page allocation tags.
> > >
> > > ...
> > >
> > >  static inline void pgalloc_tag_copy(struct folio *new, struct folio *old)
> > >  {
> > > +     union pgtag_ref_handle handle;
> > > +     union codetag_ref ref;
> > >       struct alloc_tag *tag;
> > > -     union codetag_ref *ref;
> > >
> > >       tag = pgalloc_tag_get(&old->page);
> > >       if (!tag)
> > >               return;
> > >
> > > -     ref = get_page_tag_ref(&new->page);
> > > -     if (!ref)
> > > +     if (!get_page_tag_ref(&new->page, &ref, &handle))
> > >               return;
> > >
> > >       /* Clear the old ref to the original allocation tag. */
> > >       clear_page_tag_ref(&old->page);
> > >       /* Decrement the counters of the tag on get_new_folio. */
> > > -     alloc_tag_sub(ref, folio_nr_pages(new));
> > > -
> > > -     __alloc_tag_ref_set(ref, tag);
> > > -
> > > -     put_page_tag_ref(ref);
> > > +     alloc_tag_sub(&ref, folio_nr_pages(new));
> >
> > mm-stable has folio_size(new) here, fixed up.
>
> Oh, right. You merged that patch tonight and I formatted my patchset
> yesterday :)
> Thanks for the fixup.
>
> >
> > I think we aleady discussed this, but there's a crazy amount of
> > inlining here.  pgalloc_tag_split() is huge, and has four callsites.
>
> I must have missed that discussion but I am happy to unline this
> function. I think splitting is heavy enough operation that this
> uninlining would not have be noticeable.

Posted requested uninlining at
https://lore.kernel.org/all/20241024162318.1640781-1-surenb@google.com/

> Thanks!